1. Field of the Invention
The present invention relates to a rotary electrical component provided with a push switch which is operated on and off by the axial movement of an operating shaft, thereby to operate the rotary electrical component such as a pulse switch, a variable resistor, etc.
2. Description of the Prior Art
In this type of prior art rotary electrical component with a push switch, a bearing 31 has a housing section 31a, a through hole 31b, and a collar portion 31c provided on the end to close a part of the through hole 31b as shown in FIG. 5.
Within the housing section 31a of the bearing 31 are housed a rotatable magnetic drum 32 having a hole 32a at center, and a plurality of Hall ICs 33 fixed in an opposite position to the magnetic drum 32. The rotary electrical component D which is a rotary encoder is comprised of the magnetic drum 32 and the Hall ICs 33.
The magnetic drum 32 is provided with a projection-depression portion 32b. A spring 34 fixed inside of the housing section 31a can be engaged with, and disengaged from, the projection-depression portion 32b, so that the magnetic drum 32 can make a click operation when turning.
The operating shaft 35 has a round portion 35b with a groove 35a, a non-round portion 35c connected to the round portion 35b, and a projection 35d connected to the non-round portion 35c. The operating shaft 35 is inserted into the through hole 31b of the bearing 31 and the hole 32a of the magnetic drum 32; and the round portion 35b is positioned in the collar portion 31c and the non-round portion 35c in the hole 32a.
In the groove 35a of the operating shaft 35 a metal washer 36 is fitted in contact with the inside surface of the collar portion 31c, thereby preventing accidental removal of the operating shaft 35.
The operating shaft 35 thus installed is capable of rotation and axial movement. The operating shaft 35, when turned, rotates the round portion 35b in the collar portion 31c and also rotates the magnetic drum 32 through the non-round portion 35c. Also, the operating shaft 35, when axially moved, slides between the collar portion 31c and the hole 32a.
An insulating base 37 of a synthetic resin molding is disposed to cover the open part of the housing section 31a of the bearing 31, and a push switch P is mounted in a recess 37a of the insulating base 37.
The push switch P is comprised of a stationary contact 39 embedded in the casing 38, a moving contact 40 disposed within the casing 38, a dome-shaped rubber member 41 mounted within the casing 38 and disposed to cover the moving contact 40, and a plate member 42 so disposed as to cover the open part of the casing 38.
With the push switch P mounted at the rear of a rotary electrical component D, the rubber member 41 is in a position close oppositely to a projection 35d of the operating shaft 35, to press the operating shaft 35 forwardly.
In such a rotary electrical component with a push switch, when a knob 43 attached on the operating shaft 35 is turned, the magnetic drum 32 is turned by the operating shaft 35 while making a click operation. As the magnetic drum 32 turns, the Hall IC 33 generates an output signal to thereby operate the rotary electrical component D.
When the knob 43 is depressed to move in the axial direction, the operating shaft also moves to push the rubber member 41 with the projection 35d.
Then, the rubber member 41 is pressed to deflect until it depresses the moving contact 40, which in turn contacts the stationary contact 39 to be in ON state.
When the knob 43 is released from a pressure, the rubber member 41 resets itself by its own resilience to the original position. Thus the operating shaft 35 is pushed back by the rubber member 41 until the washer 36 is locked to the collar portion 31c and at the same time the moving contact 40 returns with its own resilience to the original position to be in OFF state, thereby operating the rotary electrical component D and the push switch P.
The conventional rotary electrical component with a push switch uses a washer 36 to lock the operating shaft 35 from accidental loosening from position. As the washer 36 is needed, the quantity of component parts will increase, resulting in lowered assembling efficiency and increased cost.
The operating shaft 35, when released after being pushed, is forced back and the washer 36 hits the collar portion 31c, producing a hitting sound, which grates on ears, and moreover deteriorating the quality of the electrical component.
The operating shaft 35 makes rotation and axial movement by means of the collar portion 31c of the bearing 31. In this case, however, the small-diameter portion of the operating shaft 35 is supported, which, however, presents the problem that the operating shaft 35 can not operate smoothly.